Muffler



1 June 3, 1930. v, CRAM 1,761,971

' MUFFLER Filed June 25-, 1928 bustion chamber and through which spent which will be eflicient Patented June '3, 1930 LEROY V. OF FLINT, MICHIGAN, ASSIGNOR T0 GENERAL MOTORS CORPORATION,

OF DETROIT, MICHIGAN, A CORPORATION OF DELAWARE MUFFLER Application filed June as, 1928. Serial No. 288,115.

This invention relates to mufilers or silencers for dampening the explosion noises of an internal combustion engine or the like and particularly to the type of mufller that forms a part of the exhaust line from the engine comgases or products of combustion are expelled.

It is an object of the invention to provide an improved muffler construction that will be simple and economical in manufacture, comprise but a few readily assembled parts, and in action and unlikely to get out of order.

It is 'a further object and an important object of the invention to provide a muflier which will give to the gases inward and outward movements in succession as they progress therethrough and also a continuous circulatory or swirling movement throughout, with the result that back pressure is eliminated and the pulsation or intermittent expul sions are effectually broken up and trans formed intoa steady, continuous discharge, thereby dampening the exhaust noises.

Other incidental'objects will be apparent from the following description when taken in connection with the accompanying drawing,'wherein:

Fig. 1 is a side elevation of the preferred embodiment of the invention, portions thereof being broken away and shown in section to better illustrate the relation of the parts;

Fig. 2 is an elevation of one of the baflle walls; H L

Fig. 3v is a section on line 33 of Fig. 2;

Fig. 4 is a fragmentary elevation ofanother of the baflle walls, and

Fig. 5 is an enlarged detail sectional view taken on the line 5-5 of Fig. 4. 1

Referring to the drawing, the character 1 indicates the cylindrical casing or shell pre1terably formed either fromtubular stock or from flat sheet metal rolled to shape and joined along abutting edges. ithin the shell 1 are positioned a plurality of partition walls or bafie plates, there being four of such plates shown in the drawing and numbered 2, 3, 4 and 5, each of said walls having an annular flange welded or otherwisesecured to the wall. of the casing or shell.

15.. The end of engagement with nuts 20 with the end plate 21 by bolts 27 and nuts 28.

For convenience of assembly, the walls 2 and 3may be secured in place after being successively introduced through the opening at one end of the casing and the walls 4 and 5 similarly secured, after being inserted through the opening at the opposite end of the casing. The walls 2 and 4, which are identical, are provided with a series of louvres or inclined vanes 6 and 6, respectively, in the outer portion thereof, while the walls 3 and 5, which are also identical, have'a number of louvres or vanes 7 and 7 respectively, in their central portions. The casing is thus divided into several compartments or chambers 8, 9, 10, 11 and 12.

Positioned over one end of the casing 1, is a plate 13, having a peripheral flange 14 re-- versely bent over the end of the casing and a V central opening defined bytheannular flange the flange 15 is flared outwardly to provide a seat for the terminal bead I or ridge 16 formed on the exhaust pipe or conduit 17, the head 16 being held onits seat by a collar 18 removably secured in place by a series of bolts 19 having screw threaded which, if desired, may be welded on the inside of the end plate. 13. The opposite end of the casing is similarly closed by a plate 21, secured to the casing by the reversely bent peripheral flange 22 and having the bead 23 of the tail pipe 24 detachably held against the flared end of the annular flange 25 by the collar 26 connected It will be seen, therefore, that the construction of the mufller is extremely simple and one which can be manufactured at low cost and easily and readily assembled and introduced in the exhaust'line.

The spent gases expelled from the, engine combustion chamber through the conduit 17,

enter the chamber 8 and as they pass the wall arms the chamber 9, are given a circular or swirling movement by the twisterv blades or vanes 6 in the outer portion of the partition wall. The gas swirling around in the chamber 9 at the same time moves inwardly and flows through the openings in the central portion of the wall 3, the vanes 7 again imparting to the gas stream a swirling action. Then the swirling gases move outwardly in the chamber to pass the wall 4 again being directed in a circular path by thevanes 6,1nto the chamber 11, whence they once more move inward to reach the chamber 12 through the central openings at the louvers 7 in the wall 5, eventually passing through the tail or discharge pipe 24. v

It will be understood that the length of the m muflier and the number of bafiie walls may be varied to suit conditions. That is, more or less than two sets of alternately arranged baffle Walls may be employed.

As will be apparent, the swirling gas stream moves inward and outward as it passes through succeeding chambers and this action is found to effectually break up the intermittent expulsions and produce a uniform and steady flow through the tail pipe to atmosphere, thereby mufiiing the exhaust noises incident to engine operation.

I claim:

1. A muffler, including a casing, a plurality of partition walls in said casing, each of said walls having a series of gas whirling louvers therein that imparta swirling movement to the gases, the louvers in certain of the walls being in the outer portion thereof and the louvers in other walls being in the central portion thereof.

2. The mufller described in claim 1, where in the walls having louvers in their outer portions are arranged in alternate relation with the walls having louvers in their central portions.

I 3. A muffler including a casing, a pair of partition walls in the casing, one wall having gas whirling louvers in its outer portion and the other wall having gas whirling louvers in its central portion.

4. A muffler, including a casing for the flow of gases therethrough, a succession of partition walls dividing the easing into a series of compartments, said walls having louvers formed therein to direct the gas stream in a circular path, the louvers in alternate Walls being adjacent the center and the louvers in the other walls being adjacent the periphery, whereby the gas in addition to moving in a circular path also moves in and out as it travels through succeeding compartments.

In testimony whereof I affix my signature.

LEROY V. CRAM. 

